National origin was included in Title VII's list of protected classes: 

To ensure that illegal immigrants are given a fair chance at employment. 

As a last-minute attempt to add controversy to the legislation so that it would not be enacted. 

To ensure that employers do not make employment decisions based on preconceived notions about employees' or applicants' country of origin. 

To satisfy international critics of the legislation who suggested that the protection it afforded was simply not enough